Rotary hydraulic motor or pump



March 12, 1940. G. A. wAHLMARK Y ROTARY HYDRAULIC MOTOR 0R PUMP Filed may 17. 1937 2 sheets-sheet 1 March l2, 1940.

G. A. wAHLMARK v RTARY HYDRAULIC MOTOR 0R PUMP Filed May 17, 1937 2 Sheets-Sheet 2 f7/Wa?? ,f3/ca@ @f Patented Mar. 12, 1940 ROTARY HYDRAULIC MOTOR OR IUlvll Gunnar A. Wahlmark, Rockford, lll.

Application May 17,

1937, serial No. 143,076

1o claims; (o1. 'i4- 60) The invention relates to a fluid motor or pump and it is a general object of the invention to provide a new and improved device of that character.

5 VA more particular object of the invention is the provision in a device of that character having reciprocatory fluid handling mechanism and a rotatably mounted shaft of new and improved conversion mechanism for transforming the re. l ciprocatory motion of the fluid handling mechanism into rotary motion of the shaftor vice Y Versa.

Another object is the provision of a rotary hydraulic motor wherein fluid under pressure acts l first on a` setof reciprocating members, the

movements of whichare transferred'to 'a driven shaft having rotary motion, by a new and improved transfer device loosely the reciprocating members and having a per- .20 manent variably tiltable connection with the driven shaft. Y.

Still another'object is the provision in a device of thecharacter described of new and im-v proved means for adjusting the conversion meansv to vary the speed of the device when used as a motor or to vary the displacement of the de.- vice when used as a pum Still another object is the provision of a rotary hydraulic motor wherein fluid force is.trans ferred from a set of reciprocating members'to a rotary drive shaft which provides a new and improved means for automatically varying the.

speed `of the motor by adjustment of the means used to transfer the motion, accompanied by a manual adjustment for determining for a given occasion the maximum limit which cannot be exceeded by variation in the speed of themotor. A further object is the provision of an automati'cally adjustable, variable speed, rotary hydraulic motor in which a manual adjustment "is provided for determining the minimum limit below which the variable low speed of the motor will not be permitted to pass'.

Stilla further object rotary hydraulic motor provided with means for converting reciprocatory motion into rotary motion, which is equipped with a manually operated adjusting means for varying the speed of the motor during operation. Y Other objects and advantages will become apparent from' the following taken in connection with the accompanying drawings, in which:

Fig. `1 is. a ferred form of the invention.

engageable with is the provision of a detailed description longitudinal section of the pre- .Fig. 2 -is a Vfragmentary longitudinal section showing the shaft and valve passages rotated from the position of Fig. 1.

Fig. 3 is a Section on the line 3`3 of Fig. 1, looking in the direction ofthe arrows.

Fig. 4 is a cross section taken on the lined-4' of Fig. l, looking in the direction of the arrows. Fig. 5 isa partial'section of a modification of the device showing an aternative control ad- VFgf is a modification of the device showing a partial section devoted to a manually operated adjusting mechanism. l

While I have shown in the drawings and will herein describe ,in vdetail the preferredembodiment of my inventionjit isto be understood that I do not thereby intend to limit the invention to the specific form disclosed, but aim to cover all modifications 'and alternative constructions falling within the spirit and scope of the invention 20 .as-expressed in the appended claims.

It is further to be understood that although the operation of the invention has been described as that of a' variable'speed, reversible motor,v all of the parts; nevertheless, may be used in the 25 same relation but with the application of power reversed in order to convert it into a fluid pump. Themotor herein described contemplates the utilization of a uid under pressure, such as oil, for example, as a driving medium in order 30 to produce in the motor a vibrationless rotary motion accompanied by a considerable reserve of power. In the embodiment shown. the motor operates rst to transform the motive power supplied by the hydraulic fluidV into reciproca- 35 tory motion and then convert this motion by novel communicating or Atransfer' means into motion which rotates a drive shaft. In orderV that the speed of the motor may be changed as desired, an adjustment is provided for the com- 40 municating means which can be operated by fluid pressure from an auxiliary circuit if preferred vand which, depending upon the operative needs of the mechanism, may be additionally providedA with a hunting ldevice for adjustably determin- 45 ing either the maximum or minimum speeds at which the motor may operate.' Hydraulic fluid is supplied to the motor through an intake port from which it is conducted through a rotating. valve member formed in the drive shaft 5o to a series of cylinders containing reciprocating pistons Afrom which, after its energy has been utilized, the uid is returned through the same valve member to an exhaust port. Motion thus imparted to the pistons is taken up byra wobble 5s a wedge and pin vzo i recess 24 the cap I2 is secured in place by bolts.

plate and transformed into rotary motion to rotate a drive shaft. In order to change the speed of the motor a leverage system, shown herein as device, is used to change the rate of transformation of motion by changing the tilt of the wobble plate. The wedge may be operated either automatically by fluid pressure and a spring, or manually, a special stop being provided with the'automatic adjustment to provide a selectedmaximum or minimum speed ad- .iustment of the motor above or below which the motor cannot be operated.

There is provided for the invention a casing generally designated I for housing the various parts of the motor, which consists of several portions including a body I I, a cap I 2' forming one end of the casing, and an end plate I3 forming the other end. Rotating within the rcasing is a shaft I4 suitably journaled in a centra'l bore thereof forming the drive shaft and in turn driven through the novel transfer means. Hydraulic fluidenters an intake passage I5 for operation of the motor in one direction, from which it is conducted to a reciprocating power mechanism designated generally I6. 'I'he reciprocatory power initially produced is transferred from the mechanism I 6 by means of a wobble plate I'I to the shaft I4. Adjacent the inside end of the shaft there is an automatic adjusting mechanism indicated generally at I8, and a man. ually operated device designated generally I9 ffor controlling or limiting the action of the automatic mechanism. Tapped holes 9 are provided in the body II to secure it to a support.

The body Il has a longitudinal stepped boreV having tubular portions 22 and 23 and a wide recessed portion 24 at the end, all within the casing l0. At the end of the bodyadjacent the or other suitable means, and at the opposite extremity the end plate I3 is similarly secured. Within the body are a plurality of longitudinally disposed and annularly arranged cylindrical chambers or pockets 25 slightly narrowed in cross section at the points 26 and having a plug 2 I for closing one end. The open ends of the cylindrical chambers communicate with the recessed portion 24 of the body II. Herein the motorhas seven cylinders, shown in Figs. 3 and 4, each communicating as indicated with the recess 24 at one end and having each a radial duct 28 communicating with the smallest portion 22 of the central stepped bore. T hese ducts 28 may be formed by a drilling operation after which the outer end of the duct is closed by means of a plug 29. Also formed in the body Il are two ports, one previously designated as the intake port I5 for the hydraulic fluid, and the other here designated as 30 for exhaust of the uid, for operation of the motor in a given direction. Each of the ports communicates with the `bore 22 by means ofpassages 3Il and 32, respectively. In order to reduce the amount of materialrequired for the casing, the body II may conform on` the exterior contour to the cylindrical pockets 25 (see Fig. 3) except for an an- .nular ange adjacent the'junctions of the body with the cap I2 and with the end plate I3.

Reciprocable in each of the cylindrical chambers 25- is a reciprocatingmember here taking the form of a piston 35 having a narrower, rounded end projecting from the cylindrical chamber. These pistons have at all times a full bearing surface in the narrower portions 26 of the cylindrical pocket and in order to reduce the through the end plate A given fixed and of the motor.

'eating with the through the respective passages 3I and 32. The

in diameter than the piston, permits the end thereof to be entirely surrounded with uid and thus reduces side thrust on the piston.

Extending longitudinally and centrally of the motor is the shaft I4 which4 projects at the left I3, and which is journaled at the opposite or right hand end within the cap I2. Adjacent the projecting end there is a rotary bearing 36, located within the end plate, and a packing 31`for sealing the central aperture of the end plate within which the shaft I4 rotates. A rotary step bearing 38 provides the means' for journaling the opposite end of the shaft I4, the inner portion of the ring being secured to the shaft by means of a retaining ring 39 and by an abutting engagement with a shoulder 40 formed upon the shaft itself. A conventional pair of retaining rings maintain the ball bearings 42 in position within the ring 38.

To impart rotary motion to the shaft I4, means is provided for transforming the reciprocatory movement of the pistons 35 into rotary movement of the shaft. Herein this means takes the form of the wobble plate II having an annular outer ring 45 in engagement with the ends 35 of the pistons 35'and an inner concentric ring 46 secured to the outer ring by means of a retainer ring and bearings 48. The inner ring is pivot-4 slightly to one side of the central axis so that the mounting of the wobble plate is slightly eccentric. An inner cylindrical portion of the inside ring of the wobble plate is retained in a tilted contact with a curved bulge 5I of the drive shaft I4 by the combined action of the eccentrically positioned pin 49 and the pistons 35.

As each successive sively through its right, it tends to tilt piston 35 is moved progresworkingstroke from left to the adjacent contacting portion of the wobble plate outward toward the right. Since, however, the plate as an entirety is permanently attached to the shaft I4, the tendency to tilt successive portions of the plate actually results in the particular high point of the plate being rotated, carrying with it the shaft I4 thereby forming a means of communicating motion to the shaft from the pistons. It should be noted,'also, that the actual angle of the tilt of the wobble plate remains constant and fixed for a given speed of motor operation.

To reduce the number of rotary parts of the motor to a. minimum and thereby facilitate operation of the speed changing mechanism at all4 speeds, the drive shaft vI4 also functionsas a valve controlling the supply and the exhaust of fluid to and from the seven cylindrical chambers To that end a portion of the shaft intermediate the protruding end and the wobble l plate is suitably passaged to constitute a valve rotatable within the bore 22. Thebore at this point has formed therein the radial ducts 28 previously described and also annular internal and axially spaced grooves and 55 communiports I5 and 30, respectively.

shaft I4 in turn is formed with annular grooves 51 and 58,- respectively; complementary to the grooves 55 and 56vin the body II., .Intermediate the grooves 51 and 58 thelshaft is formed with milled cuts 59 and 88 on diametrically opposite the contrary may be true the groove duct leading therefrom may be end a portion of the aisance sides of the shaft, as seen to good advantagelin Fig. 2. The milled cut 59. communicates with 51 by means of-a pair-of diagonal passages 6I, while the cut -60 communicates with the groove 58 by means of a pair of diagonal passages 62.

The milled cuts 59 and 6|) are disposed in the plane of the radial ducts I8 and, asbest seen in Fig. 3, are each in communication'thereby with three of'thev cylinders. The duct leading to the seventh cylinder isclosed by a portion of the shaftl intermediate the cuts 59 and 60. The three cylinders communicating with one of the cuts 59 in the present instance are receiving fluid while the three cylinders in communication with the remaining cut B are discharging uid,though for reverse operation. The piston in the seventh cylinder is on dead center at the lowest point on the wobble plate and has no movement whatsoever so that the closed. As above noted, the shaft I4 may be-made to rotate in either direction depending upon whether operating fluid is supplied to the port` I5 or the port 3l).

For rotating the motor in a clockwise direction, as viewed from the right end, uid enters at the intake port I5, passes through the passages SI, 6I and the cut 59 into the cylindrical chamber 25 by way of duct 28. After its energy is expended upon the piston 35 and the shaft I4 is sufficiently rotated, the fluid returns by way of ducts 28, the cut 60, and passages 62 and 32 to the exhaust port 30.

the speed of the altered during operation, the adjusting mechanism I8 ha-s been provided, whose function it is to vary the tilt of the wobble plate. A change in speed is accomplished by reason of the fact that when the angle of tilt of the wobble plate is decreased the pistons 35 reciprocate through a shorter distance. Less fluid is required to fill the unoccupied portion of the cylindrical chamber 25 and hence for fluid supplied at a given pressure and volume the movement of the pistons is much more rapid. Conversely, when the tiltv of the wobble plate is relatively great, the reciprocat-y ing motion of the'pistons 35 is correspondingly great, and since considerably more uid is required to ll the lower portion of the cylindrical pocket in order to drive each piston to its maximum movement, a longer time is taken for this portion of the operation, which results in operation at a slower speed.

To vary the tilt of the wobble plate, leverage is applied by means of a shifting mechanism comprising in this instance a wedge device carried by the shaft. To accommodate the device the end of the drive shaft I4 adjacent the wobble plate has formed therein an axial passage 65 and has disposed at an angle to the axial passage a somewhat radially directed passage 66. Within the radial passage, a pin 61 is positioned which slides freely back and forth and contacts at one cylindrical interior 50 of wobble plate. Extending within the axial passage 65 is a rod 68 which has a wedge shaped face 69 at the inside end positioned in sliding contact with the adjacent end of the pin 61. When the rod is extended inward, the wedge 69 tends to force the. pin 61 outward and to change the tilt of to a flatter plane. As the rod 68 is withdrawn, the wobble plate, due partially to the unequal leverage produced by the eccentricity of its the inside ring of the motor may be theA wobble plate A mounting, is forced more driving the `pin 61 back against the nowl adjacent narrower portion of the wedge shaped face 69 of the rod 68.

As provided herein, the rod, together with theV pin, rotates with the drive shaft I4. Any connection therefore with the rod of a means to impart endwise motion toit will be a rotatable connection.

In the preferred form of the device shown in Fig. 1, parting this endwise motion to the rod in order to change the speed ofthe motor. This automatic means comprises a cylindrical chamber v 10 formed within the cap I2 having slidably positioned therein a piston head 1I. The rod 68 previously referred to is swivelly connected to the piston headI 1I by means of a roller bearing 12 secured therein by a4 threaded ring 13. The pis--l ton head is so positioned within the cyindrical chamber 1f'that it divides the space into two compartments, one 14 on the left or inner side, the other 15 at the outside end. Located within the compartment 14 is a pressure element shown herein as comprising a helically coiled spring 16 supported on a ring 11 at one end and bearing against the piston head,1I at the other end so that its tendency is to force the piston head out- Ward, thereby to withdraw the rod 68 and permit the wobbleplate to occupy av position wherein it is tilted a maximum amount, which is the position for low speed of the motorf A drain port 18 communicates with the compartment- 14 for conducting back to a supply tank any quantity of fluid which may collect there due to leakage past the pistons. v

The compartment 15 is sealed and has a threaded port 18 for connection with a source of auxiliary fluid under pressure. This source may be the main fluid supply when the .mechanism is operating as a motor or may be an auxiliary supply. When fluid is admitted through the port 18 into the compartment 15, the pressure tends to force the piston head 1I inward toward the left and overcome -the force of the spring 16. Motion of the piston head in this direction tends to flatten the tilt of the wobble plate and thereby to increase the speed of the motor.

There is additionally provided the manually operated limiting device I9 for limiting the low or minimum limit below which variations in low speed of the device are not permitted to take place. To perform this function, a pin 80 is secured in the cap I2 by means lar 8| .to which the pin is by means of a nut 82. The pin has a head 83 located within the compartment 15 where it may be brought into contact with the adjacent face an automatic means is provided for imof an adjusting colnon-rotatably fixed into a tilted passioni of the piston head 1|.A Mounted upon said face ofthe pistonis a guide sleeve 84 which surrounds the head 83 ofthe pin.

The pin 80 is retained in the cap portion I2 of the casingwithin an aperture 85 and adjacent the aperture is a series of packing rings 8B clamped into position by a packing nut 81, in order to form a fluid-tight seal against' leakage from the compartment 15.

By means of the structure just recited, there is provided an automatic pressure operated speed changer for the rotary hydraulicmotor capable of transforming the force supplied by fluid at a constant volume into rotary motion variable with respect to speed and power. In addition, manual means is provided for'limiting the low speed to `which the motor will automatically be reduced shank of the pin 80' extends.

except that a pin 80' upon release of the applied pressure used in the first instance to determine the high speed nt operation.

As an alternative arrangement, it is sometimes desirable to have an adjustable high speed limit for the motor. Mechanism for supplying the adjustment is shown in Fig. 5 and is desig-l nated generally I9. 'I'he operation of this modified feature is to limit the extent of movement of a piston head 1|' towardn the left when under pressure, in order to control the application of the pressure when used to increase the motor speed.

For this purpose, the main vice are essentially the same as shown in Fig. 1, is provided having a length the pin 80 previously described. Also inside compartment and attached to the piston head 1| is a modified form 84 of a guide sleeve. This particular form has a closed end portion 90 forming a shoulder 9| and a central aperture 92 through which the A head 83' of the pin 80' provides in this instance an annular abutment 93 at the inside edge. The pin is fixed to an adjustable collar 8|' inthe customary manner by a-lock nut 82' and is sealed liquid-tight in the cap |2' by means 86' and packing ring 8 It will-be noted inthe position shown, which is the initial or lowest slightly shorter than by a slight amount, permitting the end portion 90 of 84 to abut the bottom face 94 of the compartment 15.

When it is desired to adjust the motor in order to limit the rate beyond which variations in high speed of the motor are not permitted to take place,` the adjusting collar 8| is screwed in or out in order to set the head 83' of the pin in a desired position. Then, when iiuid under pressure is introduced through port 18' into the compartment 15', the piston head 1|' is driven inward toward the left. At some point, depending upon the position of the head 83. of the pin, the shoulder 9| of the guide sleeve will come into contact with the abutment 93 of the pinand prevent the piston head from moving any further toward the left. This in turn prevents the fiattening of the tilt of the `wobble plate beyond a certain amount, thereby determining the maximum speed of the motor. This adjustment can be made while the motor is running or when at rest.

When the pressure is released, a spring 16 acting in a manner similar to the spring 16 of Fig. 1, immediately returns the piston head 1 to the position shown in Fig. 5, which is, as previously noted, the lowest speed position or the position occupied at rest.

Attention is directed in this connection to the fact that for eitherthe preferred form shown in Fig. 1,or the modified form of Fig. 3, fluidl introduced under pressure into the compartment 15 is customarily an auxiliary supply of fluid. Furthermore, whenever the fluid is an auxiliary supply rather than from the main fluid lines, such a supply may be operated either manually through a conventional type of valve (not shown) or automatically as,for example, by valves of the usual sort operated by dogs properly positioned on the moving elements of yany machine with which the motor might be used. A

Still another modification is shown in Fig. 6,

portions of the de` of the customary packing |2" is somewhat modified v1n form. A manually this sort can be used to change the speed at which the motor operates, either while the motor is at rest or while it is operating under a load.

As shown in Fig. 6, the head I2 has a threaded aperture |00 at the outer end in which is inserted a threaded block |0|. A rod 68" constructed substantially in the form shown in Fig. 1- is journaled in the block 0 bearing ring |02 secured in place by a retaining ring |03. The block is shown provided with a shank |04 the end |05 of which is squared olf to receive a wrench or crank. At the outside end of the aperture |00 a packing |06 is inserted in order to form a fluid-tight joint and a drain |01 is provided for conducting back to the supply tank any iiuid which might leak into the space formed inside the cap by the aperture 00.

In order that whatever adjustment at which the device is set may remain constant, africtionally operated locking means is provided. At o'ne side of the aperture |00 is a small radially which opens into the aperture |00 at the threaded portion. In the bottom of the passage is positioned a shoe-like plug |08. 'I'he plug is positioned so that it bears directly upon the threaded exterior of the block 0|. This plug is releasably held in place by means of a coiled spring |00 retained in position by a screw plug ||0. 'I'he tension of the4 spring |09 can be increased or diminished a desired amount by screwing the plug ||0 in or out.

It will be seen, therefore, from the drawings and the accompanying description, that there has been provided a rotary fluid motor of a very precise type which operates vunder a high starting torque and whose speed can be adjusted either manually or automatically by small increments of any desired amount and which, by such a fine control over adjustment, is adapted to work requiring the highest degree of precision.

I claim is my invention:

1. In a uid handling mechanism having a by means of a casing, a drive shaft member journaled in the ^with the first element said rod endwise in order to change the position` of the pin in contact therewith and thereby vary the tilt of the wobble plate.

2. In a fluid handling mechanism of the character described having, in combination, a. casing, a shaft rotatably journaled in the casing, a pivotally mounted wobble plate, and means for adwobble platex'comprising a the wobble plate, a presjusting the tilt of the rst element engaging sure responsive device for adjusting the wobble plate between high andllow limits of adjustment, manually actuable limiting means cooperable (with the device for selectively determining one in the casing cooperable arcanos of the limits of adjustment comprising a rod exwobble plate, means slidable in said passage and tending slidably within the casing and a cap aperture having contact with the wobble plate fixed to the projecting end of the rod and threadat one end, and projecting from the shaft at ed onto the casing to effect longitudinal shift of the other end and means for moving said last 5 the rod by rotation of the cap, sealing means be;- mention Ymeans to adjust the angular position 5 tween the rod and casing, and means on the of the wobble plate on the shaft. pressure responsive device cooperating with the '7. A fluid handling mechanism of the charrod to determ e onel of the limits of adjustment. acter described having, in combination, a drive 3. In a fluid handling mechanism, a shaft, a Shaft, a wobble plate carried by the shaft and l0 wobble plate pivotally mounted on said shaft, andadjustable angularly thereon, a pivot pin for the 10 means for adjusting the tilt of the' wobble plate wobble plate extending transversely through said comprising means slidable longitudinally of the shaft and eccentrically on one side of the shaft shaft and having a beveled end providing a cam axis, 'and meansl for adjusting the wobble plate surface, and means interposed between Said allglllarly 0n Said Din Comprising device movwobble plate and the beveled end of said first ably mounted on said shaft and having a portion 15 mentioned means for adjusting the tilt of the engaging the wobble plate onthe other side of wobble plate as the first mentioned means is the shaft axis. shifted longitudinally of said shaft. A 8. A fluid handlingmechanism of the character 4. In a fluid handling mechanism, a shaft, an described having, in combination, a drive shaft,

annular wobble plate surrounding said shaft and a wobble plate carried by the shaft and adiust- 2o pivotally mounted thereon eccentrically of the able angulal'ly thereon, a pivot pin for the wobble shaft, and means for adjusting the tilt of the plate extending transversely through said shaft wobble plate comprising a pin slidably mounted `andeccentrically of the shaft axis, and means in said shaft for movement generally radially of for sdiustlng the wobble plete angularly on seid the shaft and at right angles to the iournal on pin.

which said wobble plate is pivoted, a rod extend- 9. A fluid handling mechanism having. in 00ming slidably within said shaft and having at its bination, a drive shaft, a tiltable wobble plate inner end a beveled surface, said pin at one end associated with the shaft, adjusting means for engaging sai beveled surface and at the other changing the Ltilt of the wobble plate comprising 3o end engaging said wobble plate to change the an axial passage at one end of theshaft and e 3o tilt thereof as said rod is shifted longitudinally connecting aperture in the'shaft disposed at an of the shaft, and means for shifting the rod lonangle to the tilt of the wobble plate, a pin slidable gitudinally. a in said aperture having contact with the wobble 5. A uid handling mechanism of thecharplate at one end and extending into the axial unter described having; in combination, a, drive passage 0f the Shaft at the Other end, a rod elf- 35 shaft, a wobble plate carried'by the shaft, and tendable axially into the shaft having its one means for adjusting the wobble plate angularly end shaped for progressive varying contact with on the shaft including an axial passage in one the other end 0.! the Pin and the other end eX- end of the shaft, an intersecting aperture in the tending outward from the shaft, and means for I n shaft disposed at an angle to the tilt of the moving said rod relatively to the shaft for caus- 40 .wobble plate, means slidable in said passage and lng seid one end to shift the pin and thereby aperture having contact with the wobble plate proportionately vary the tilt of the wobble plate. at one end and projecting from the shaft at the 10. A fluid handling mechanism of the charother end, and means for moving said last menacter described having, in combination, av drive tioned means to adjust the angular position of shaft, a wobble plate carried by the shaft and 45 the wobble plate on the shaft. adjustable anglllarly thereon, a pivot pin for the 6. A fluid handling mechanism of the character wobble plate extending transversely through said described having, ln combination, a drive shaft., shaft and eccentrically on one side of the shaft a wobble plate carried by the shaft, a pivot pin axis, and means for adjusting the wobble plate so for the wobble plate extending transversely angulerly on said pin comprising e device mov- 5o through the shaft eccentrically of the shaft axis, ably mounted on said shaftand having a portion and means foradjusting the wobble plate angv.- enaging the wobble plate on the other side of' larly on the shaft including an axial passage in the shaft axis and means including a piston for one end of the shaft, an intersecting aperture in actuating said e. the shaft disposed at an angle to the tilt of the GUNNAR A. WAHLMARK 5g 

